1. Field of the Invention
This invention relates to a radio receiver designed to receive program identification signals transmitted simultaneously with specific news information, such as traffic information, weather reports etc.
2. Prior Art
The traffic information system (called the ARI) developed in West Germany uses a low frequency signal, in the AM band, as the 57 Khz band identification signal. This signal is sent continuously while traffic information is being transmitted. As a result, a means for sensing the said low frequency signal must be provided. The output from this means of detection is used as the key for listening to the traffic information.
This method is efficient for the transmission of a single program such as a traffic information broadcast. However, this system has limitations when an attempt is made to broaden it for use in listening to several different programs, such as weather reports, news etc., which involves the use of multiple identification codes.